From 3d36f4298ba91fbdec6bc56aa7bb0663cba6ab0c Mon Sep 17 00:00:00 2001 From: Youling Tang Date: Sat, 10 Dec 2022 22:39:48 +0800 Subject: LoongArch: Switch to relative exception tables Similar to other architectures such as arm64, x86, riscv and so on, use offsets relative to the exception table entry values rather than their absolute addresses for both the exception location and the fixup. However, LoongArch label difference because it will actually produce two relocations, a pair of R_LARCH_ADD32 and R_LARCH_SUB32. Take simple code below for example: $ cat test_ex_table.S .section .text 1: nop .section __ex_table,"a" .balign 4 .long (1b - .) .previous $ loongarch64-unknown-linux-gnu-gcc -c test_ex_table.S $ loongarch64-unknown-linux-gnu-readelf -Wr test_ex_table.o Relocation section '.rela__ex_table' at offset 0x100 contains 2 entries: Offset Info Type Symbol's Value Symbol's Name + Addend 0000000000000000 0000000600000032 R_LARCH_ADD32 0000000000000000 .L1^B1 + 0 0000000000000000 0000000500000037 R_LARCH_SUB32 0000000000000000 L0^A + 0 The modpost will complain the R_LARCH_SUB32 relocation, so we need to patch modpost.c to skip this relocation for .rela__ex_table section. Signed-off-by: Youling Tang Signed-off-by: Huacai Chen --- scripts/mod/modpost.c | 13 +++++++++++++ scripts/sorttable.c | 2 +- 2 files changed, 14 insertions(+), 1 deletion(-) (limited to 'scripts') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 2c80da0220c3..9321c0a05ffd 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1523,6 +1523,14 @@ static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) #define R_RISCV_SUB32 39 #endif +#ifndef EM_LOONGARCH +#define EM_LOONGARCH 258 +#endif + +#ifndef R_LARCH_SUB32 +#define R_LARCH_SUB32 55 +#endif + static void section_rela(const char *modname, struct elf_info *elf, Elf_Shdr *sechdr) { @@ -1564,6 +1572,11 @@ static void section_rela(const char *modname, struct elf_info *elf, ELF_R_TYPE(r.r_info) == R_RISCV_SUB32) continue; break; + case EM_LOONGARCH: + if (!strcmp("__ex_table", fromsec) && + ELF_R_TYPE(r.r_info) == R_LARCH_SUB32) + continue; + break; } sym = elf->symtab_start + r_sym; /* Skip special sections */ diff --git a/scripts/sorttable.c b/scripts/sorttable.c index fba40e99f354..0f2beda80478 100644 --- a/scripts/sorttable.c +++ b/scripts/sorttable.c @@ -312,12 +312,12 @@ static int do_file(char const *const fname, void *addr) case EM_PARISC: case EM_PPC: case EM_PPC64: + case EM_LOONGARCH: custom_sort = sort_relative_table; break; case EM_ARCOMPACT: case EM_ARCV2: case EM_ARM: - case EM_LOONGARCH: case EM_MICROBLAZE: case EM_MIPS: case EM_XTENSA: -- cgit v1.2.3-58-ga151 From 26bc82441250f2e01621f5b26606a4f6926ee3ad Mon Sep 17 00:00:00 2001 From: Youling Tang Date: Sat, 10 Dec 2022 22:39:59 +0800 Subject: LoongArch: extable: Add `type` and `data` fields This is a LoongArch port of commit d6e2cc564775 ("arm64: extable: add `type` and `data` fields"). Subsequent patches will add specialized handlers for fixups, in addition to the simple PC fixup we have today. In preparation, this patch adds a new `type` field to struct exception_table_entry, and uses this to distinguish the fixup and other cases. A `data` field is also added so that subsequent patches can associate data specific to each exception site (e.g. register numbers). Handlers are named ex_handler_*() for consistency, following the example of x86. At the same time, get_ex_fixup() is split out into a helper so that it can be used by other ex_handler_*() functions in the subsequent patches. Signed-off-by: Youling Tang Signed-off-by: Huacai Chen --- arch/loongarch/include/asm/asm-extable.h | 15 +++++++++++---- arch/loongarch/include/asm/extable.h | 11 +++++++++++ arch/loongarch/kernel/vmlinux.lds.S | 3 +-- arch/loongarch/mm/extable.c | 7 ++++++- scripts/sorttable.c | 2 +- 5 files changed, 30 insertions(+), 8 deletions(-) (limited to 'scripts') diff --git a/arch/loongarch/include/asm/asm-extable.h b/arch/loongarch/include/asm/asm-extable.h index 74f8bc75472a..634bd770e3c4 100644 --- a/arch/loongarch/include/asm/asm-extable.h +++ b/arch/loongarch/include/asm/asm-extable.h @@ -2,17 +2,22 @@ #ifndef __ASM_ASM_EXTABLE_H #define __ASM_ASM_EXTABLE_H +#define EX_TYPE_NONE 0 +#define EX_TYPE_FIXUP 1 + #ifdef __ASSEMBLY__ -#define __ASM_EXTABLE_RAW(insn, fixup) \ +#define __ASM_EXTABLE_RAW(insn, fixup, type, data) \ .pushsection __ex_table, "a"; \ .balign 4; \ .long ((insn) - .); \ .long ((fixup) - .); \ + .short (type); \ + .short (data); \ .popsection; .macro _asm_extable, insn, fixup - __ASM_EXTABLE_RAW(\insn, \fixup) + __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_FIXUP, 0) .endm #else /* __ASSEMBLY__ */ @@ -20,15 +25,17 @@ #include #include -#define __ASM_EXTABLE_RAW(insn, fixup) \ +#define __ASM_EXTABLE_RAW(insn, fixup, type, data) \ ".pushsection __ex_table, \"a\"\n" \ ".balign 4\n" \ ".long ((" insn ") - .)\n" \ ".long ((" fixup ") - .)\n" \ + ".short (" type ")\n" \ + ".short (" data ")\n" \ ".popsection\n" #define _ASM_EXTABLE(insn, fixup) \ - __ASM_EXTABLE_RAW(#insn, #fixup) + __ASM_EXTABLE_RAW(#insn, #fixup, __stringify(EX_TYPE_FIXUP), "0") #endif /* __ASSEMBLY__ */ diff --git a/arch/loongarch/include/asm/extable.h b/arch/loongarch/include/asm/extable.h index b571c89705d1..92612b4364a1 100644 --- a/arch/loongarch/include/asm/extable.h +++ b/arch/loongarch/include/asm/extable.h @@ -17,10 +17,21 @@ struct exception_table_entry { int insn, fixup; + short type, data; }; #define ARCH_HAS_RELATIVE_EXTABLE +#define swap_ex_entry_fixup(a, b, tmp, delta) \ +do { \ + (a)->fixup = (b)->fixup + (delta); \ + (b)->fixup = (tmp).fixup - (delta); \ + (a)->type = (b)->type; \ + (b)->type = (tmp).type; \ + (a)->data = (b)->data; \ + (b)->data = (tmp).data; \ +} while (0) + bool fixup_exception(struct pt_regs *regs); #endif diff --git a/arch/loongarch/kernel/vmlinux.lds.S b/arch/loongarch/kernel/vmlinux.lds.S index b3309a5e695b..efecda0c2361 100644 --- a/arch/loongarch/kernel/vmlinux.lds.S +++ b/arch/loongarch/kernel/vmlinux.lds.S @@ -4,6 +4,7 @@ #include #define PAGE_SIZE _PAGE_SIZE +#define RO_EXCEPTION_TABLE_ALIGN 4 /* * Put .bss..swapper_pg_dir as the first thing in .bss. This will @@ -53,8 +54,6 @@ SECTIONS . = ALIGN(PECOFF_SEGMENT_ALIGN); _etext = .; - EXCEPTION_TABLE(16) - .got : ALIGN(16) { *(.got) } .plt : ALIGN(16) { *(.plt) } .got.plt : ALIGN(16) { *(.got.plt) } diff --git a/arch/loongarch/mm/extable.c b/arch/loongarch/mm/extable.c index 08a9a7d6357a..fd2395221cff 100644 --- a/arch/loongarch/mm/extable.c +++ b/arch/loongarch/mm/extable.c @@ -30,5 +30,10 @@ bool fixup_exception(struct pt_regs *regs) if (!ex) return false; - return ex_handler_fixup(ex, regs); + switch (ex->type) { + case EX_TYPE_FIXUP: + return ex_handler_fixup(ex, regs); + } + + BUG(); } diff --git a/scripts/sorttable.c b/scripts/sorttable.c index 0f2beda80478..83cdb843d92f 100644 --- a/scripts/sorttable.c +++ b/scripts/sorttable.c @@ -304,6 +304,7 @@ static int do_file(char const *const fname, void *addr) switch (r2(&ehdr->e_machine)) { case EM_386: case EM_AARCH64: + case EM_LOONGARCH: case EM_RISCV: case EM_S390: case EM_X86_64: @@ -312,7 +313,6 @@ static int do_file(char const *const fname, void *addr) case EM_PARISC: case EM_PPC: case EM_PPC64: - case EM_LOONGARCH: custom_sort = sort_relative_table; break; case EM_ARCOMPACT: -- cgit v1.2.3-58-ga151 From a0a458fbd6f2317832e2d74acdbfa2451c3f4b8f Mon Sep 17 00:00:00 2001 From: Qing Zhang Date: Sat, 10 Dec 2022 22:40:15 +0800 Subject: LoongArch/ftrace: Add recordmcount support Recordmcount utility under scripts is run, after compiling each object, to find out all the locations of calling _mcount() and put them into specific seciton named __mcount_loc. Then the linker collects all such information into a table in the kernel image (between __start_mcount_loc and __stop_mcount_loc) for later use by ftrace. This patch adds LoongArch specific definitions to identify such locations. And on LoongArch, only the C version is used to build the kernel now that CONFIG_HAVE_C_RECORDMCOUNT is on. Acked-by: Steven Rostedt (Google) Signed-off-by: Qing Zhang Signed-off-by: Huacai Chen --- arch/loongarch/Kconfig | 2 ++ scripts/recordmcount.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+) (limited to 'scripts') diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index 72a41e08f9f4..8b81cf9a6503 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -85,11 +85,13 @@ config LOONGARCH select HAVE_ARCH_TRANSPARENT_HUGEPAGE select HAVE_ASM_MODVERSIONS select HAVE_CONTEXT_TRACKING_USER + select HAVE_C_RECORDMCOUNT select HAVE_DEBUG_STACKOVERFLOW select HAVE_DMA_CONTIGUOUS select HAVE_EBPF_JIT select HAVE_EXIT_THREAD select HAVE_FAST_GUP + select HAVE_FTRACE_MCOUNT_RECORD select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER select HAVE_GENERIC_VDSO diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c index cce12e1971d8..e30216525325 100644 --- a/scripts/recordmcount.c +++ b/scripts/recordmcount.c @@ -38,6 +38,14 @@ #define R_AARCH64_ABS64 257 #endif +#ifndef EM_LOONGARCH +#define EM_LOONGARCH 258 +#define R_LARCH_32 1 +#define R_LARCH_64 2 +#define R_LARCH_MARK_LA 20 +#define R_LARCH_SOP_PUSH_PLT_PCREL 29 +#endif + #define R_ARM_PC24 1 #define R_ARM_THM_CALL 10 #define R_ARM_CALL 28 @@ -441,6 +449,28 @@ static int arm64_is_fake_mcount(Elf64_Rel const *rp) return ELF64_R_TYPE(w8(rp->r_info)) != R_AARCH64_CALL26; } +static int LARCH32_is_fake_mcount(Elf32_Rel const *rp) +{ + switch (ELF64_R_TYPE(w(rp->r_info))) { + case R_LARCH_MARK_LA: + case R_LARCH_SOP_PUSH_PLT_PCREL: + return 0; + } + + return 1; +} + +static int LARCH64_is_fake_mcount(Elf64_Rel const *rp) +{ + switch (ELF64_R_TYPE(w(rp->r_info))) { + case R_LARCH_MARK_LA: + case R_LARCH_SOP_PUSH_PLT_PCREL: + return 0; + } + + return 1; +} + /* 64-bit EM_MIPS has weird ELF64_Rela.r_info. * http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf * We interpret Table 29 Relocation Operation (Elf64_Rel, Elf64_Rela) [p.40] @@ -558,6 +588,7 @@ static int do_file(char const *const fname) break; case EM_IA_64: reltype = R_IA64_IMM64; break; case EM_MIPS: /* reltype: e_class */ break; + case EM_LOONGARCH: /* reltype: e_class */ break; case EM_PPC: reltype = R_PPC_ADDR32; break; case EM_PPC64: reltype = R_PPC64_ADDR64; break; case EM_S390: /* reltype: e_class */ break; @@ -589,6 +620,10 @@ static int do_file(char const *const fname) reltype = R_MIPS_32; is_fake_mcount32 = MIPS32_is_fake_mcount; } + if (w2(ehdr->e_machine) == EM_LOONGARCH) { + reltype = R_LARCH_32; + is_fake_mcount32 = LARCH32_is_fake_mcount; + } if (do32(ehdr, fname, reltype) < 0) goto out; break; @@ -610,6 +645,10 @@ static int do_file(char const *const fname) Elf64_r_info = MIPS64_r_info; is_fake_mcount64 = MIPS64_is_fake_mcount; } + if (w2(ghdr->e_machine) == EM_LOONGARCH) { + reltype = R_LARCH_64; + is_fake_mcount64 = LARCH64_is_fake_mcount; + } if (do64(ghdr, fname, reltype) < 0) goto out; break; -- cgit v1.2.3-58-ga151